Installation; Setting The Hdsl Line Voltage Option - ADC HiGain HLU-200 User Manual

350-200-111-02, Issue 2
I
NSTALLATION
Upon receipt of the equipment, visually inspect it for signs of damage. If the
equipment has been damaged in transit, immediately report the extent of
damage to the transportation company and to ADC.
S
ETTING THE
The HDSL line powering voltage is set by the S1 switch. Bipolar (BIP) sets
the HDSL line voltage to +65 Vdc on loop 2 (+100 Vdc for doubler circuits)
and -65 Vdc on loop 1 (-100 Vdc for doubler circuits). This setting reduces
the maximum ground referenced voltage but applies positive voltage to the
cable pairs, which could accelerate corrosion on the cable pairs. Unipolar
(UNI) sets the HDSL line voltage to 0 Vdc on loop 2 and to -130 Vdc on loop
1 (-200 Vdc for doubler circuits). This setting keeps the HDSL cable pair
voltage at or below ground potential, thereby avoiding corrosion problems
caused by cable voltages more positive than ground.
The line voltage power supply, used for both options, is ground referenced
and also ground isolated by 200 k
due to induced noise currents and large surge voltages that are ground
referenced. Ground isolation also reduces ground-fault currents, which
improves product safety. The safety issue depends solely on the differential
voltage across Loop 1 and Loop 2 and is independent of the S1 setting.
HLU-200 List 1A
HDSL L
INE
9
. The ground isolation reduces problems
October 4, 1999
V O
OLTAGE

Installation

PTION
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